Engadget got to play with Salfish. "Overall, we came away reasonably impressed with Sailfish OS, despite experiencing only a fraction of its functionality. Performance was decent considering the N950's relatively modest single-core underpinnings - then again, MeeGo's no slouch either."

Audio/video calling (as with XMPP/Jingle) will require additional UI. Even on N9, their default client didn't get video calling UI right away. Not that it's impossible - I hope Sailfish will take care of it soon enough.